The invention relates to medical and surgical devices and in particular to medical and surgical devices used in conjunction with patient breathing problems. Specifically, the invention relates to tracheostomy, an operation for providing an airway for patients requiring mechanical assistance in breathing, and for conduction of anesthetic gas when the tube is placed in the trachea through the mouth or nose.
At present, the size (both calibre and length), the shape, and the overall construction of the standard tracheostomy tubes that are in use are somewhat traditional, being almost identical with that found illustrated in Mackensie's book which was published in 1880.
Initially, the tracheostomy was used almost exclusively to divert the air from an obstruction of the larynx, regardless of the cause. The tracheostomy tube was a rigid device and remains so today. With the advent of closed systems of ventilatory support used in anesthesia, an inflatable cuff was added to the device.
Recently, the tracheostomy has become critical to modern respiratory care and it is more than just an airway, it is the conduit of survival when attached to a mechanical ventilator. The effectiveness, however, is often negated by complications that are associated with the tracheostomy tubes that are in use at this time.
Among those patients requiring tracheostomy there are anatomical variations of the depth of the trachea within the neck. These differences are seen in the long neck and in the short heavy neck.
Because deviations from normal anatomical conditions are common, placing one of the currently available rigid tracheostomy tubes into a proper and a constant aligned position within the tracheal lumen becomes virtually impossible. The lack of flexibility in adjusting a tracheostomy tube to each individual trachea can require constant attention of the staff caring from these patients. Such conditions and problems can render the patentcy of the airway uncertain.
No less critical are the complications of prolonged tracheostomy. Such complications are tracheomalacia with progression to fistulae between the trachea and the esophagus, erosion of the anterior trachea and the innominate artery (often a fatal event), and later tracheal stenosis which sometimes necessitates surgical correction.
To solve the aforementioned problems and to make tracheostomy a safer modality of care, the present invention of a new tracheostomy tube has been developed. The present invention has four distinctive features. Those four distinctive features are a precision cuff fitted to each trachea, a flexible tube that will conform to any depth of the trachea within the neck, a self-locking clip that adjusts the tube securely to any neck regardless of the depth of the trachea, and a malleable but rigid obturator for ease of insertion.
The precision cuff is fitted to each trachea. The cuff of tracheostomy tubes of the prior art are not provided with this feature. Most tracheostomy tubes that are in use now and in the prior art have a soft cuff that, when inflated, assumes a fusiform shape presenting a narrow surface in contact with the trachea mucosa. Any prolonged pressure above twenty-five torr increases the risk of tracheal necrosis.
A more or less convoluted type or fluted cuff, with constricting bands to limit distention to the specific size of each trachea, is provided by the present invention. The average tracheal lumen size in the adult male is 25 mm and in the female 23 mm, with a standard deviation of 4 mm each way.
Accurate size of each trachea is determined, before the opening is made in the trachea. This is done by placing a marker of known size on the neck and then obtaining a radiograph and measuring the film to determine the tracheal lumen size in relation to the known size of the radiographed marker. Thus, each cuff used is the precise size for each trachea as ascertained by this measurement procedure.
The advantage of the precision convoluted-like or fluted cuff is to equalize the pressure over a longer segment of the mucosa by the use of the constricting bands limiting the size in the cuff constrictions. This also insures uniform diameter and controlled expansion.
The convoluted-like or fluted cuff and the manner of assuring the precise size in relation to the patient's trachea, effects a more complete seal at a lower pressure on the tracheal mucosa. Each convolution-like roll or flute creates a seal and the plurality of seals increases the total sealing effectiveness, thus avoiding the problem of the fusiform configuration which is inherent in the single chamber cuff.
It is to be noted that the precision cuff of the present invention has been described as convolution-like or fluted on the exterior surface. Note that it is not the same as a common corrugated configuration. The plurality of adjoining adjacent circular flutes interface with each other at the sides. The flutes are somewhat like convolutions or partial toroids upon adjacent toroids, better described as being fluted. The aforementioned constricting bands each are fitted into the crease between each two adjoining and adjacent flutes.
In the prior art, some attempt has been made to change the aforementioned fusiform configuration to a convolution-like arrangement. Actually the configuration taught in the prior art is more like a corrugated configuration. The corrugated-like configuration of the prior art is not the same as the closely fluted surface of the present invention and it does not accomplish the same objective, particularly it is to be noted that no constricting bands between flutes is taught in the prior art.
Some spiral reinforcement has also been taught in the prior art, but this is not the same as the constricting circular-like bands taught in the present invention. In the present invention, when the precision cuff is inflated to a predetermined low pressure, the constricting bands limit the outside diameter to the predetermined precision fit in the trachea. There is no such predetermination or limitation in the prior art.
In the Static Tracheostomy Tube the tube design remains constant at 8 mm inside diameter and the cuff size becomes the variable in selecting the tracheostomy device to be used in a given patient. This is a unique and novel feature not provided in the prior art.
It is to be understood that the aforementioned 8 mm inside diameter for the static tracheostomy tube of this invention is the preferred embodiment, but that it may be varied either way without departing from the scope or intent of this invention.
The tracheostomy tube of this invention is flexible. The non-rigid contour and configuration will conform to any depth of the trachea within the neck. With the cuff inflated the non-rigid contour and configuration of the tracheostomy tube will always be in the center position of the lumen of the trachea.
By having the tracheostomy tube centered in the lumen of the trachea it avoids having the motion of the tip of the tube causing erosion of the anterior trachea and the adjacent innominate artery. In a like manner, the centering of the tracheostomy tube in the lumen of the trachea also avoids erosion posteriorly into the adjacent esophagus.
The flexible tracheostomy tube of this invention has a corrugated configuration. The corrugated configuration of the flexible tracheostomy tube absorbs and cushions the thrust created by the pulsations of the mechanical respirator. This absorbing and cushioning effect eliminates the abrasive motion of the tracheostomy tubes of the prior art to the trachea mucosa. Thus, the present invention allows long term respiratory support while decreasing the likelihood of fistulae. The corrugated configuration also prevents accidental kinking of the tube that would cut off the flow of air with disastrous results.
The present invention's self-locking clip adjusts the tracheostomy tube securely to any neck, regardless of the depth of the trachea, without displacing the tip of the tube from the central position within the lumen of the trachea.
A malleable, but rigid, obturator is provided for the Static Tracheostomy Tube for ease in insertion.
A plurality of sizes of the Static Tracheostomy Tube is provided in order to meet the needs for the range of diameters of the trachea that may be found in patients when making the precision fit by the aforementioned measurement procedure.
In addition to inserting the Static Tracheostomy Tube through an opening in the neck area, the tube can also be inserted into the trachea through the mouth or through the nose.
Regarding the flexible tube means it is to be noted that it is in a corrugated form of circular-like rings that provides for great flexibility and at the same time provides a means that will absorb the thrust of the pulsations of mechanical respiratory equipment connected to the tracheostomy tube. This configuration and shock absorbing characteristic is not present in the prior art.
In the prior art some attempt has been made to make the tubes flexible by using spiral reinforcement and by serating the outside surface. However, these steps are not the same as the corrugated like configuration of the present invention which is not only flexible, but also absorbs the thrust and pulsations of mechanical equipment connected to the tracheostomy tube.
It is, therefore, an object of the invention to provide a Static Tracheostomy Tube for a reliable airway for patients requiring mechanical assistance in breathing.
It is another object of the invention to provide a Static Tracheostomy Tube that avoids the complications of prolonged tracheostomy.
It is also an object of the invention to provide a Static Tracheostomy Tube that makes tracheostomy a safer modality of care.
It is still another object of the invention to provide a Static Tracheostomy Tube that has a precision cuff fitted to each trachea under treatment.
It is yet another object of the invention to provide a Static Tracheostomy Tube that has a flexible (but rigid) tube that will conform to any depth of the trachea within the neck of a patient.
It is yet still another object of the invention to provide a Static Tracheostomy Tube that has a self-locking clip that adjusts the tube securely to any neck, regardless of the depth of the trachea.
It is also still another object of the invention to provide a Static Tracheostomy Tube that has a malleable, but rigid, obturator for ease of insertion.
It is still another object of the invention to embody all of the features of this design into a endotracheal tube passed via the mouth or nose for use in conduction of gases used in anesthesia.
Further objects and advantages of the invention will become more apparent in the light of the following description of the preferred embodiments.